Arsenic transfer and biotransformation in a fully characterized freshwater food web

作者：Foust Richard D Jr^*; Bauer Anne Marie; Costanza Robinson Molly; Blinn Dean W; Prince Roger C; Pickering Ingrid J; George Graham N

来源：Coordination Chemistry Reviews, 2016, 306: 558-565.

DOI：10.1016/j.ccr.2015.03.005

• Arsenic
• Biotransformation
• Diminution
• Food web
• Montezuma Well

X-ray absorption near edge spectroscopy (XANES) was combined with ICP-MS to understand arsenic transfer and transformation within the freshwater Montezuma Well (central Arizona, USA) food web. Montezuma Well water contains 110 mu gL(-1) arsenic (100% H3AsO4), which was shown previously to originate from ore deposits approximately 30 km to the west, and transported underground to enter Montezuma Well through vents in the bottom of this collapsed travertine spring. The Montezuma Well food web contains three trophic levels with only five organisms in the top two levels, making it possible to account for the arsenic in >90% of the biomass of the food web. Arsenic diminution generally occurs between trophic levels, with 702 mg kg(-1) As in the primary producers, 3.4 mg kg(-1) As in the second trophic level, and <1.3 mg kg(-1) As for the top-tier of the littoral zone food web. A notable exception to the biodiminution trend is the very high total arsenic content (2810 mg kg(-1)) of Motobdella montezuma, an endemic leech and top predator. The biotransformed (sulfur-coordinated) arsenic in M. montezuma appears to be present almost entirely on the surface of the organism, possibly suggesting a detoxification mechanism. XANES sample spectra were fit by a linear combination of model arsenic compound spectra and indicated that arsenic enters the food web from the Well water entirely as inorganic As(V) and is transformed within the food web into more reduced and organic arsenic species, including sulfur-coordinated and methylated compounds.

• 出版日期2016-1-1